thao

Most popular questions and responses by thao
  1. Chemistry

    The value of delta H for the reaction below is -1107kj. 2Ba (s) + O2 (g) -> 2BaO (s) How many kJ of heat are released when 5.75 g of BaO (s) is produced? Here is how I approached this problem: 1. Converted 5.75 g of BaO to mol: 5.75g x (1mol BaO/153.3g

    asked on May 23, 2011
  2. Chemistry

    A 500 mL metal cylinder holding 0.100 moles of helium gas is known to rupture at a pressure of 10 atmospheres. At what temperature, in °C, will the container fail? Here is what I came up with: T= (1.00mol x 0.0821 LxATM/KxMOL) / 10atm x 0.5L =0.01642K

    asked on April 25, 2011
  3. Chemistry

    Ideal gas law question A 4.0 liter container has two gases inside, neon and argon. It is known that at 18 °C, the total pressure of the combined gases is 0.850 atm. If it is known that there are 0.100 moles of neon in the container, how many moles of

    asked on April 25, 2011
  4. Science 8 grade

    A little aluminum boat (mass of 14.50g) has a volume of 450.00cm3. The boat is placed in a small pool of water and carefully filled with pennies. If each penny has a mass of 2.50g, how many pennies can be added to the boat before it sinks?

    asked on October 16, 2008
  5. Chemistry

    How many joules of heat are needed to heat 25.0 g of ice at -5.0 degrees celcius to a final temperature of 40.0 degrees celcius? The specific heat of ice is 2.1 j. Our teacher mention to consider the state of water present at 40.0 degrees celcius which is

    asked on April 6, 2011
  6. Chemistry

    How many grams of ice are needed to cool 250 ml of water from 75 degrees celcius to 5 degrees celcius?

    asked on April 12, 2011
  7. Physics

    A gas is confined in a 0.47-m-diameter cylinder by a piston, on which rests a weight. The mass of the piston and weight together is 150 kg. The atmospheric pressure is 101 kPa. (a)What is the force (in Nt) exerted on the gas by the piston, the weight and

    asked on January 14, 2013
  8. Chemistry Lab

    If 12.50 mL of 0.324 M HCl is diluted to 250.00 mL, what is the concentration of HCl in the final solution?

    asked on May 10, 2011
  9. Chemistry

    Write a balance ionic and net equation for the following: KOH + HC2H3O2 I came up with the following but think this is wrong: KOH + HC2H3O2 -> H2O (l) + KC2H3O2 (aq)

    asked on May 13, 2011
  10. Chemistry

    If a certain gas has a density of 2.34 g/L at 27.0C and 742 torr, what is the molar mass of this gas? I am not sure what formula to use to solve this problem.

    asked on April 27, 2011
  11. Physics

    A box is given a push so that it slides across the floor. How far will it go, given that the coefficient of kinetic friction is 0.16 and the push imparts an initial speed of 4.2 m/s?

    asked on December 20, 2010
  12. Science

    Calculate the density of bromine if 586g of the substance occupies 188mL

    asked on October 16, 2008
  13. Chemistry Lab

    You need 123 mL of 0.245 M NaOH solution for a certain experiment, and the only solution available in the lab is 1.252 M. How many mL OF THE 1.252 M NaOH would you need?

    asked on May 10, 2011
  14. 8th grade Social Studies

    Which colony was the first to promote religious tolerance?

    asked on September 20, 2008
  15. Chemistry

    100 ml graduated cylinder containing 50 ml of water, drop 100g piece of brass into the water what height does the water rise in the graduated cylinder?

    asked on February 20, 2015
  16. 8th grade Social Studies

    How might the colony of Georgia have been different if Oglethorpe's plan had succeeded?

    asked on September 20, 2008
  17. Chemistry

    If the molar volume of an ideal gas is 22.4 L/mol, calculate the theoretical density of hydrogen gas at STP. Not sure what formula to use with this question. Thanks.

    asked on April 27, 2011
  18. Chemistry

    If 12.0 gram of ice are dropped in 150. ml of water at 45 degrees celcius, what is the final temperature of the water?

    asked on April 12, 2011
  19. Science

    At what tempertures is your element a solid, liquid, or gas? Why or how?

    asked on December 30, 2008
  20. Chemistry

    A 25.00 mL sample of seawater taken from a depth of 1000 meters weighs 25.75 g. What is the density of seawater?

    asked on August 29, 2011
  21. 8th grade Social Studies

    Why were slaves in high demand in the southern colonies?

    asked on September 20, 2008
  22. 8th grade Social Studies

    Which colony was the first to promote religious tolerance

    asked on September 20, 2008
  23. Chemistry Lab

    Using the molarity of fromic acid (HCOOH): 0.1033 Calculate the percent by mass of fromic acid in unknown solution. Assume the density of aqueous fromic acid solution is 1.000 g/mL. Need help setting up this problem. Thank you.

    asked on May 16, 2011
  24. math

    A number subtracted from 13is the quotient of -128 and 8 . Find the number. pls help, thxs

    asked on February 17, 2016
  25. 8th grade Social Studies

    Why did more enslaved Africa live in South Carolina than did white settlers?

    asked on September 20, 2008
  26. Science

    At what tempertures is calcium a solid, liquid, or gas?

    asked on December 30, 2008
  27. Algebra

    Write an equation of the line containing the point (o,-4) and perpendicular to the line y=1/3x+5

    asked on November 5, 2008
  28. math

    the minimum size dance floor that the prom committee is considering 30 by 30 . they assume that this size will allow 100 couples to be on the dance floor at once. how many square feet of dance space per couple does this size allow?

    asked on October 25, 2008
  29. math

    the minimum size dance floor that the prom committee is considering is 30 by 30. they assume that this size will allow 100 couples to be on the dance floor at once. how many square feet of dance space per couple does this size allow.

    asked on October 21, 2008
  1. math

    1343.33

    posted on September 8, 2017
  2. math 5

    9.34 8.5

    posted on September 8, 2017
  3. Accounting

    A. $6,853

    posted on May 21, 2013
  4. physics

    1/2at^2

    posted on August 28, 2012
  5. Chemistry

    I came up with this but not sure if it's right: D = 1mol/22.4L x 2.02g/1mol = 0.0902g/L

    posted on April 27, 2011
  6. Chemistry

    I recalculated the problem and got it correct. Thank you.

    posted on April 25, 2011
  7. Chemistry

    I was giving the answer key with the correct answer at 336 C. Now i'm really confused... Can someone explain.

    posted on April 25, 2011
  8. Chemistry

    Makes perfect sense. Thank you.

    posted on April 12, 2011
  9. Chemistry

    After some sleep, i was able to come up with the following. It's still not 36 degrees, but close. Can some check my calculation? [mass ice x heat fusion] + [mass melted ice x specific heat water x (Tfinal-Tinitial)] + [mass water x specific heat water x

    posted on April 12, 2011
  10. Chemistry

    Filling in the equation, here is what I have. Still not coming up with 36 degrees. Please help: [mass ice x heat fusion] 12.0g x 334j/g [mass melted ice x specific heat water x (Tfinal-Tinitial)] 12.0g x 4.18j/g x 45 (Delta T is 45 because temp of ice from

    posted on April 12, 2011
  11. Science 8 grade

    n=174.2 right? How can you do that?

    posted on October 16, 2008
  12. 8th grade Social Studies

    so how about another questions? Can you help me?

    posted on September 20, 2008
  13. 8th grade Social Studies

    Section 1: The Southern Colonies

    posted on September 20, 2008
  14. 8th grade Social Studies

    yes

    posted on September 20, 2008
  15. 8th grade Social Studies

    Analyze Why did more enslaved Africa live in South Carolina than did white settlers?

    posted on September 20, 2008
  16. 8th grade Social Studies

    i did but i don't understand that question

    posted on September 20, 2008
  17. 8th grade Social Studies

    so Ms.Sue is that your answer for this question?

    posted on September 20, 2008
  18. Algebra-please check my answers

    1,2,3,4

    posted on March 17, 2008